diff --git a/CHANGES.rst b/CHANGES.rst
index 055c1db..cc90a13 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -4,6 +4,8 @@ Changelog
 4.0a2 (unreleased)
 ------------------
 
+- Remove mechanize based testbrowser support.
+
 - Use `@implementer` class decorator.
 
 4.0a1 (2016-09-09)
diff --git a/src/ZServer/Testing/testbrowser.py b/src/ZServer/Testing/testbrowser.py
deleted file mode 100644
index 243837f..0000000
--- a/src/ZServer/Testing/testbrowser.py
+++ /dev/null
@@ -1,167 +0,0 @@
-##############################################################################
-#
-# Copyright (c) 2006 Zope Foundation and Contributors.
-# All Rights Reserved.
-#
-# This software is subject to the provisions of the Zope Public License,
-# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
-# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
-# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
-# FOR A PARTICULAR PURPOSE.
-#
-##############################################################################
-"""Support for using zope.testbrowser from Zope2.
-
-Mostly just copy and paste from zope.testbrowser.testing.
-"""
-
-import cStringIO
-import httplib
-import urllib2
-
-import mechanize
-from zExceptions import status_reasons
-from zope.testbrowser import browser
-
-from ZServer.Testing.doctest_functional import http
-
-
-class PublisherConnection(object):
-
-    def __init__(self, host, timeout=None):
-        self.caller = http
-        self.host = host
-
-    def set_debuglevel(self, level):
-        pass
-
-    def _quote(self, url):
-        # the publisher expects to be able to split on whitespace, so we have
-        # to make sure there is none in the URL
-        return url.replace(' ', '%20')
-
-    def request(self, method, url, body=None, headers=None):
-        """Send a request to the publisher.
-
-        The response will be stored in ``self.response``.
-        """
-        if body is None:
-            body = ''
-
-        if url == '':
-            url = '/'
-
-        url = self._quote(url)
-        # Extract the handle_error option header
-        handle_errors_key = 'X-Zope-Handle-Errors'
-        handle_errors_header = headers.get(handle_errors_key, True)
-        if handle_errors_key in headers:
-            del headers[handle_errors_key]
-        # Translate string to boolean.
-        handle_errors = {'False': False}.get(handle_errors_header, True)
-
-        # Construct the headers.
-        header_chunks = []
-        if headers is not None:
-            for header in headers.items():
-                header_chunks.append('%s: %s' % header)
-            headers = '\n'.join(header_chunks) + '\n'
-        else:
-            headers = ''
-
-        # Construct the full HTTP request string, since that is what the
-        # ``HTTPCaller`` wants.
-        request_string = (method + ' ' + url + ' HTTP/1.1\n' +
-                          headers + '\n' + body)
-        self.response = self.caller(request_string, handle_errors)
-
-    def getresponse(self):
-        """Return a ``urllib2`` compatible response.
-
-        The goal of ths method is to convert the Zope Publisher's reseponse to
-        a ``urllib2`` compatible response, which is also understood by
-        mechanize.
-        """
-        real_response = self.response._response
-        status = real_response.getStatus()
-        reason = status_reasons[real_response.status]
-        headers = []
-        # Convert header keys to camel case. This is basically a copy
-        # paste from ZPublisher.HTTPResponse
-        for key, val in real_response.headers.items():
-            if key.lower() == key:
-                # only change non-literal header names
-                key = "%s%s" % (key[:1].upper(), key[1:])
-                start = 0
-                l = key.find('-', start)
-                while l >= start:
-                    key = "%s-%s%s" % (
-                        key[:l], key[l + 1:l + 2].upper(), key[l + 2:])
-                    start = l + 1
-                    l = key.find('-', start)
-            headers.append((key, val))
-        # get the cookies, breaking them into tuples for sorting
-        cookies = real_response._cookie_list()
-        headers.extend(cookies)
-        headers.sort()
-        headers.insert(0, ('Status', "%s %s" % (status, reason)))
-        headers = '\r\n'.join('%s: %s' % h for h in headers)
-        content = real_response.body
-        return PublisherResponse(content, headers, status, reason)
-
-
-class PublisherResponse(object):
-    """``mechanize`` compatible response object."""
-
-    def __init__(self, content, headers, status, reason):
-        self.content = content
-        self.status = status
-        self.reason = reason
-        self.msg = httplib.HTTPMessage(cStringIO.StringIO(headers), 0)
-        self.content_as_file = cStringIO.StringIO(self.content)
-
-    def read(self, amt=None):
-        return self.content_as_file.read(amt)
-
-    def close(self):
-        """To overcome changes in mechanize and socket in python2.5"""
-        pass
-
-
-class PublisherHTTPHandler(urllib2.HTTPHandler):
-    """Special HTTP handler to use the Zope Publisher."""
-
-    http_request = urllib2.AbstractHTTPHandler.do_request_
-
-    def http_open(self, req):
-        """Open an HTTP connection having a ``urllib2`` request."""
-        # Here we connect to the publisher.
-        return self.do_open(PublisherConnection, req)
-
-
-class PublisherMechanizeBrowser(mechanize.Browser):
-    """Special ``mechanize`` browser using the Zope Publisher HTTP handler."""
-
-    default_schemes = ['http']
-    default_others = ['_http_error', '_http_request_upgrade',
-                      '_http_default_error']
-    default_features = ['_redirect', '_cookies', '_referer', '_refresh',
-                        '_equiv', '_basicauth', '_digestauth']
-
-    def __init__(self, *args, **kws):
-        self.handler_classes = mechanize.Browser.handler_classes.copy()
-        self.handler_classes["http"] = PublisherHTTPHandler
-        self.default_others = [cls for cls in self.default_others
-                               if cls in mechanize.Browser.handler_classes]
-        mechanize.Browser.__init__(self, *args, **kws)
-
-
-class Browser(browser.Browser):
-    """A Zope ``testbrowser` Browser that uses the Zope Publisher."""
-
-    def __init__(self, url=None):
-        mech_browser = PublisherMechanizeBrowser()
-        # override the http handler class
-        mech_browser.handler_classes["http"] = PublisherHTTPHandler
-        super(Browser, self).__init__(url=url, mech_browser=mech_browser)
diff --git a/src/ZServer/ZPublisher/tests/exception_handling.txt b/src/ZServer/ZPublisher/tests/exception_handling.txt
deleted file mode 100644
index fe2c8e9..0000000
--- a/src/ZServer/ZPublisher/tests/exception_handling.txt
+++ /dev/null
@@ -1,202 +0,0 @@
-Exception handling
-------------------
-
-These tests capture the current behavior. Maybe some of that behavior should
-be changed. The behavior caused by handleErrors=False shows only up in tests.
-
-Set exception hook:
-
-    >>> from ZServer.ZPublisher.exceptionhook import EXCEPTION_HOOK
-    >>> import Zope2
-    >>> setattr(Zope2, 'zpublisher_exception_hook', EXCEPTION_HOOK)
-
-Create the browser object we'll be using.
-
-    >>> from ZServer.Testing.testbrowser import Browser
-    >>> browser = Browser()
-    >>> # XXX: browser has no API for disabling redirects
-    >>> browser.mech_browser.set_handle_redirect(False)
-
-Create the objects that are raising exceptions.
-
-    >>> dummy = app.test_folder_1_._setObject('foo', ExceptionRaiser1())
-    >>> dummy = app.test_folder_1_._setObject('bar', ExceptionRaiser2())
-    >>> dummy = app.test_folder_1_._setObject('baz', ExceptionRaiser3())
-
-Handle AttributeError.
-
-    >>> app.test_folder_1_.foo.exception = AttributeError('ERROR VALUE')
-
-    >>> browser.handleErrors = True
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    HTTPError: HTTP Error 500: Internal Server Error
-
-    >>> browser.handleErrors = False
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    AttributeError: ERROR VALUE
-    >>> browser.contents
-
-Handle ImportError.
-
-    >>> app.test_folder_1_.foo.exception = ImportError('ERROR VALUE')
-
-    >>> browser.handleErrors = True
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    HTTPError: HTTP Error 500: Internal Server Error
-
-    >>> browser.handleErrors = False
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    ImportError: ERROR VALUE
-    >>> browser.contents
-
-Handle zope.publisher.interfaces.NotFound.
-
-    >>> from zope.publisher.interfaces import NotFound
-    >>> app.test_folder_1_.foo.exception = NotFound('OBJECT','NAME')
-
-    >>> browser.handleErrors = True
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    HTTPError: HTTP Error 404: Not Found
-
-    >>> browser.handleErrors = False
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    NotFound: Object: 'OBJECT', name: 'NAME'
-    >>> browser.contents
-
-Don't handle SystemExit, even if handleErrors is True.
-
-    >>> app.test_folder_1_.foo.exception = SystemExit('ERROR VALUE')
-
-    >>> browser.handleErrors = True
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    SystemExit: ERROR VALUE
-    >>> browser.contents
-
-    >>> browser.handleErrors = False
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    SystemExit: ERROR VALUE
-    >>> browser.contents
-
-Handle zExceptions.Redirect.
-
-    >>> from zExceptions import Redirect
-    >>> app.test_folder_1_.foo.exception = Redirect('LOCATION')
-
-    >>> browser.handleErrors = True
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    HTTPError: HTTP Error 302: Found
-    >>> browser.contents
-    ''
-    >>> browser.headers['Location']
-    'LOCATION'
-
-    >>> browser.handleErrors = False
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    Redirect: LOCATION
-    >>> browser.contents
-
-Handle zExceptions.Unauthorized raised by the object. We take the
-'WWW-Authenticate' header as a sign that HTTPResponse._unauthorized was called.
-
-    >>> from zExceptions import Unauthorized
-    >>> app.test_folder_1_.foo.exception = Unauthorized('ERROR VALUE')
-
-    >>> browser.handleErrors = True
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    HTTPError: HTTP Error 401: Unauthorized
-    >>> browser.headers['WWW-Authenticate']
-    'basic realm="Zope2"'
-
-    >>> browser.handleErrors = False
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    Unauthorized: ERROR VALUE
-    >>> browser.contents
-
-And the same with unicode error value.
-
-    >>> app.test_folder_1_.foo.exception = Unauthorized(u'ERROR VALUE \u03A9')
-
-    >>> browser.handleErrors = True
-    >>> browser.open('http://localhost/test_folder_1_/foo')
-    Traceback (most recent call last):
-    ...
-    HTTPError: HTTP Error 401: Unauthorized
-    >>> browser.headers['WWW-Authenticate']
-    'basic realm="Zope2"'
-
-    >>> browser.handleErrors = False
-    >>> try:
-    ...     browser.open('http://localhost/test_folder_1_/foo')
-    ... except Unauthorized, e:
-    ...     e._message == u'ERROR VALUE \u03A9'
-    ... else:
-    ...     print "Unauthorized not raised"
-    True
-    >>> browser.contents
-
-Handle zExceptions.Unauthorized raised by BaseRequest.traverse. We take the
-'WWW-Authenticate' header as a sign that HTTPResponse._unauthorized was called.
-
-    >>> browser.handleErrors = True
-    >>> browser.open('http://localhost/test_folder_1_/bar')
-    Traceback (most recent call last):
-    ...
-    HTTPError: HTTP Error 401: Unauthorized
-    >>> 'You are not authorized to access this resource.' in browser.contents
-    True
-    >>> browser.headers['WWW-Authenticate']
-    'basic realm="Zope2"'
-
-    >>> browser.handleErrors = False
-    >>> browser.open('http://localhost/test_folder_1_/bar')
-    Traceback (most recent call last):
-    ...
-    Unauthorized: You are not authorized to access this resource...
-    >>> browser.contents
-
-Handle zExceptions.Forbidden raised by BaseRequest.traverse. 'traverse'
-converts it into zExceptions.NotFound if we are not in debug mode.
-
-    >>> browser.handleErrors = True
-    >>> browser.open('http://localhost/test_folder_1_/baz')
-    Traceback (most recent call last):
-    ...
-    HTTPError: HTTP Error 404: Not Found
-    >>> '<p><strong>Resource not found</strong></p>' in browser.contents
-    True
-    >>> '<p><b>Resource:</b> index_html</p>' in browser.contents
-    True
-
-    >>> browser.handleErrors = False
-    >>> browser.open('http://localhost/test_folder_1_/baz')
-    Traceback (most recent call last):
-    ...
-    NotFound: ...
-    ...<h2>Site Error</h2>
-    ...<p><strong>Resource not found</strong></p>...
-    ...<p><b>Resource:</b> index_html</p>...
-    >>> browser.contents
diff --git a/src/ZServer/ZPublisher/tests/test_exception_handling.py b/src/ZServer/ZPublisher/tests/test_exception_handling.py
deleted file mode 100644
index 9ede712..0000000
--- a/src/ZServer/ZPublisher/tests/test_exception_handling.py
+++ /dev/null
@@ -1,51 +0,0 @@
-##############################################################################
-#
-# Copyright (c) 2010 Zope Foundation and Contributors.
-#
-# This software is subject to the provisions of the Zope Public License,
-# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
-# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
-# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
-# FOR A PARTICULAR PURPOSE.
-#
-##############################################################################
-""" Functional tests for exception handling.
-"""
-
-import unittest
-
-from OFS.SimpleItem import SimpleItem
-
-from ZServer.Testing.doctest_functional import FunctionalDocFileSuite
-
-
-class ExceptionRaiser1(SimpleItem):
-
-    def index_html(self):
-        """DOCSTRING
-        """
-        raise self.exception
-
-
-class ExceptionRaiser2(ExceptionRaiser1):
-
-    __roles__ = ()
-
-
-class ExceptionRaiser3(SimpleItem):
-
-    def index_html(self):
-        return 'NO DOCSTRING'
-
-
-def test_suite():
-    return unittest.TestSuite([
-        FunctionalDocFileSuite(
-            'exception_handling.txt',
-            globs={
-                'ExceptionRaiser1': ExceptionRaiser1,
-                'ExceptionRaiser2': ExceptionRaiser2,
-                'ExceptionRaiser3': ExceptionRaiser3,
-            }),
-    ])